/* zutil.c -- target dependent utility functions for the compression library
 * Copyright (C) 1995-2005 Jean-loup Gailly.
 * For conditions of distribution and use, see copyright notice in zlib.h
 */

/* @(#) $Id$ */

#include "zutil.h"

#ifndef NO_DUMMY_DECL
struct internal_state      {
	int dummy;
}; /* for buggy compilers */
#endif

const char* const z_errmsg[10] = {
	"need dictionary",     /* Z_NEED_DICT       2  */
	"stream end",          /* Z_STREAM_END      1  */
	"",                    /* Z_OK              0  */
	"file error",          /* Z_ERRNO         (-1) */
	"stream error",        /* Z_STREAM_ERROR  (-2) */
	"data error",          /* Z_DATA_ERROR    (-3) */
	"insufficient memory", /* Z_MEM_ERROR     (-4) */
	"buffer error",        /* Z_BUF_ERROR     (-5) */
	"incompatible version",/* Z_VERSION_ERROR (-6) */
	""
};


const char* ZEXPORT zlibVersion()
{
	return ZLIB_VERSION;
}

uLong ZEXPORT zlibCompileFlags()
{
	uLong flags;

	flags = 0;

	switch(sizeof(uInt)) {
		case 2:
			break;

		case 4:
			flags += 1;
			break;

		case 8:
			flags += 2;
			break;

		default:
			flags += 3;
	}

	switch(sizeof(uLong)) {
		case 2:
			break;

		case 4:
			flags += 1 << 2;
			break;

		case 8:
			flags += 2 << 2;
			break;

		default:
			flags += 3 << 2;
	}

	switch(sizeof(voidpf)) {
		case 2:
			break;

		case 4:
			flags += 1 << 4;
			break;

		case 8:
			flags += 2 << 4;
			break;

		default:
			flags += 3 << 4;
	}

	switch(sizeof(z_off_t)) {
		case 2:
			break;

		case 4:
			flags += 1 << 6;
			break;

		case 8:
			flags += 2 << 6;
			break;

		default:
			flags += 3 << 6;
	}

#ifdef DEBUG
	flags += 1 << 8;
#endif
#if defined(ASMV) || defined(ASMINF)
	flags += 1 << 9;
#endif
#ifdef ZLIB_WINAPI
	flags += 1 << 10;
#endif
#ifdef BUILDFIXED
	flags += 1 << 12;
#endif
#ifdef DYNAMIC_CRC_TABLE
	flags += 1 << 13;
#endif
#ifdef NO_GZCOMPRESS
	flags += 1L << 16;
#endif
#ifdef NO_GZIP
	flags += 1L << 17;
#endif
#ifdef PKZIP_BUG_WORKAROUND
	flags += 1L << 20;
#endif
#ifdef FASTEST
	flags += 1L << 21;
#endif
#ifdef STDC
#  ifdef NO_vsnprintf
	flags += 1L << 25;
#    ifdef HAS_vsprintf_void
	flags += 1L << 26;
#    endif
#  else
#    ifdef HAS_vsnprintf_void
	flags += 1L << 26;
#    endif
#  endif
#else
	flags += 1L << 24;
#  ifdef NO_snprintf
	flags += 1L << 25;
#    ifdef HAS_sprintf_void
	flags += 1L << 26;
#    endif
#  else
#    ifdef HAS_snprintf_void
	flags += 1L << 26;
#    endif
#  endif
#endif
	return flags;
}

#ifdef DEBUG

#ifndef verbose
	#define verbose 0
#endif
int z_verbose = verbose;

void z_error(m)
char* m;
{
	fprintf(stderr, "%s\n", m);
	exit(1);
}
#endif

/* exported to allow conversion of error code to string for compress() and
 * uncompress()
 */
const char* ZEXPORT zError(err)
int err;
{
	return ERR_MSG(err);
}

#if defined(_WIN32_WCE)
	/* The Microsoft C Run-Time Library for Windows CE doesn't have
	* errno.  We define it as a global variable to simplify porting.
	* Its value is always 0 and should not be used.
	*/
	int errno = 0;
#endif

#ifndef HAVE_MEMCPY

void zmemcpy(dest, source, len)
Bytef* dest;
const Bytef* source;
uInt  len;
{
	if(len == 0) return;

	do {
		*dest++ = *source++; /* ??? to be unrolled */
	} while(--len != 0);
}

int zmemcmp(s1, s2, len)
const Bytef* s1;
const Bytef* s2;
uInt  len;
{
	uInt j;

	for(j = 0; j < len; j++) {
		if(s1[j] != s2[j]) return 2 * (s1[j] > s2[j]) - 1;
	}

	return 0;
}

void zmemzero(dest, len)
Bytef* dest;
uInt  len;
{
	if(len == 0) return;

	do {
		*dest++ = 0;  /* ??? to be unrolled */
	} while(--len != 0);
}
#endif


#ifdef SYS16BIT

#ifdef __TURBOC__
/* Turbo C in 16-bit mode */

#  define MY_ZCALLOC

/* Turbo C malloc() does not allow dynamic allocation of 64K bytes
 * and farmalloc(64K) returns a pointer with an offset of 8, so we
 * must fix the pointer. Warning: the pointer must be put back to its
 * original form in order to free it, use zcfree().
 */

#define MAX_PTR 10
/* 10*64K = 640K */

local int next_ptr = 0;

typedef struct ptr_table_s {
	voidpf org_ptr;
	voidpf new_ptr;
} ptr_table;

local ptr_table table[MAX_PTR];
/* This table is used to remember the original form of pointers
 * to large buffers (64K). Such pointers are normalized with a zero offset.
 * Since MSDOS is not a preemptive multitasking OS, this table is not
 * protected from concurrent access. This hack doesn't work anyway on
 * a protected system like OS/2. Use Microsoft C instead.
 */

voidpf zcalloc(voidpf opaque, unsigned items, unsigned size)
{
	voidpf buf = opaque; /* just to make some compilers happy */
	ulg bsize = (ulg)items * size;

	/* If we allocate less than 65520 bytes, we assume that farmalloc
	 * will return a usable pointer which doesn't have to be normalized.
	 */
	if(bsize < 65520L) {
		buf = farmalloc(bsize);

		if(*(ush*)&buf != 0) return buf;
	} else {
		buf = farmalloc(bsize + 16L);
	}

	if(buf == NULL || next_ptr >= MAX_PTR) return NULL;

	table[next_ptr].org_ptr = buf;

	/* Normalize the pointer to seg:0 */
	*((ush*)&buf + 1) += ((ush)((uch*)buf - 0) + 15) >> 4;
	*(ush*)&buf = 0;
	table[next_ptr++].new_ptr = buf;
	return buf;
}

void  zcfree(voidpf opaque, voidpf ptr)
{
	int n;

	if(*(ush*)&ptr != 0) {  /* object < 64K */
		farfree(ptr);
		return;
	}

	/* Find the original pointer */
	for(n = 0; n < next_ptr; n++) {
		if(ptr != table[n].new_ptr) continue;

		farfree(table[n].org_ptr);

		while(++n < next_ptr) {
			table[n - 1] = table[n];
		}

		next_ptr--;
		return;
	}

	ptr = opaque; /* just to make some compilers happy */
	Assert(0, "zcfree: ptr not found");
}

#endif /* __TURBOC__ */


#ifdef M_I86
/* Microsoft C in 16-bit mode */

#  define MY_ZCALLOC

#if (!defined(_MSC_VER) || (_MSC_VER <= 600))
	#define _halloc  halloc
	#define _hfree   hfree
#endif

voidpf zcalloc(voidpf opaque, unsigned items, unsigned size)
{
	if(opaque) opaque = 0;  /* to make compiler happy */

	return _halloc((long)items, size);
}

void  zcfree(voidpf opaque, voidpf ptr)
{
	if(opaque) opaque = 0;  /* to make compiler happy */

	_hfree(ptr);
}

#endif /* M_I86 */

#endif /* SYS16BIT */


#ifndef MY_ZCALLOC /* Any system without a special alloc function */

#ifndef STDC
	extern voidp  malloc OF((uInt size));
	extern voidp  calloc OF((uInt items, uInt size));
	extern void   free   OF((voidpf ptr));
#endif

voidpf zcalloc(opaque, items, size)
voidpf opaque;
unsigned items;
unsigned size;
{
	if(opaque) items += size - size;  /* make compiler happy */

	return sizeof(uInt) > 2 ? (voidpf)malloc(items * size) :
	       (voidpf)calloc(items, size);
}

void  zcfree(opaque, ptr)
voidpf opaque;
voidpf ptr;
{
	free(ptr);

	if(opaque) return;  /* make compiler happy */
}

#endif /* MY_ZCALLOC */
